Inducibility of ventricular arrhythmias in early repolarization syndrome and Brugada syndrome: From the J-wave associated with prior cardiac event (J-PREVENT) registry

Background: Although electrophysiological study is often performed in Brugada syndrome (BrS) to assess inducibility of ventricular arrhythmias (VA), the utility of electrophysiological study in early repolarization syndrome (ERS) remains unknown. The aim of the present multi-center observational study was to compare inducibility of VA in ERS with BrS, and to investigate any association between inducibility and recurrence of arrhythmic events in these patients. Methods: The J-PREVENT registry consists of patients with early repolarization or Brugada type 1 ECGs, a history of prior cardiac events, and no structural heart disease. Patients in the registry with implantable cardioverter-defibrillators (ICDs) and who underwent electrophysiological study were enrolled. VA inducibility was assessed by programmed electrical stimulation performed at two different sites in the right ventricle with up to three extrastimuli. The occurrence of VA during follow-up was determined by interrogation of the patients׳ ICDs. Results: Of the 79 patients studied (72 males, mean age 44±13 years), 21 patients (27%) had ERS, and 58 had BrS, 20 of whom also had early repolarization in the inferolateral leads. VA was induced in 9 patients (43%) and 45 (78%) with ERS and BrS, respectively (p=0.006). During a median follow-up of 1453 days, occurrence rate of VA was similar between ERS and BrS (p=0.35). Inducibility was not associated with occurrence of VA in either syndrome. Conclusions: In patients with ERS with prior history of cardiac events, VA was induced in 43% of patients during electrophysiological study, approximately half that of BrS. Inducibility was not associated with occurrence of VA during follow-up, although this was true of BrS patients as well. Electrophysiological study may play a limited role in risk stratification in ERS

Seasonal, weekly, and circadian distribution of ventricular fibrillation in patients with J-wave syndrome from the J-PREVENT registry

Background: Ventricular fibrillation (VF) in Brugada syndrome (BrS) is known to occur more frequently during nighttime and from spring to early summer. In this study, we investigated whether early repolarization syndrome (ERS) has the same seasonal, weekly, and circadian distribution of VF events as BrS using data from the “J-wave associated with prior cardiac event” (J-PREVENT) registry. Methods: The study included 90 consecutive patients with BrS and 31 patients with ERS during a mean follow-up of 49±37 months. Follow-up data from implantable cardioverter-defibrillators were evaluated in all cases. Results: In patients with ERS, the circadian distribution of VF episodes differed among the four 6-h periods, with a significant peak from midnight to 6:00 am (p<0.01) similar to that observed in BrS patients. However, VF occurred more frequently on weekends in patients with ERS, whereas on weekdays in patients with BrS (p<0.01). The months of peak VF occurrence also differed between the groups, with the frequency of VF episodes at peak between December and March in ERS patients and between March and June in BrS patients. In ERS patients, VF events had an inverse correlation with air temperature (r=−0.726, p<0.01). Conclusions: ERS and BrS patients show similar nighttime increases in the occurrence of VF, but different seasonal and weekly distributions, suggesting a pathophysiological difference between the two syndromes